1. Field of the Invention
The present invention relates to a display device and a manufacturing method thereof.
2. Description of the Related Art
In recent years, techniques for improvement in performance (e.g., reduction in power consumption or increase in definition) of a display device have been developed.
Examples of the display device include a liquid crystal display device, an electroluminescent display device (also referred to as an EL display device), and the like.
As a transistor for driving a display element (a liquid crystal element, an EL element, or the like) in the display device, a transistor in which a channel formation region includes a silicon semiconductor, a transistor in which a channel formation region includes a metal oxide semiconductor, or the like can be used. For example, a display device disclosed in Patent Document 1 is an example of a display device including, as a transistor for driving a display element, a transistor in which a channel formation region includes a metal oxide semiconductor.